Vacuum chambers are widely used in various applications for providing interruption-free environment for analytical processes. For example, a typical electron microscope operates to inspect a sample placed in a vacuum chamber, e.g. at a typical pressure of Pv≈10−5-10−6 Torr. At such low pressures many materials behave as volatile substances and may produce vapor which might contaminate sample or samples located within the chamber. For example, evaporated Hydrocarbon (HC) molecules, typically originating from various oils used for lubricating moving platforms within a vacuum chamber, often adsorb on the chamber's walls and contaminate samples which are located in the chamber (even for a short time).
Some conventional techniques for reducing the amount of contaminating molecules within a vacuum chamber utilize injection of free radicals (and especially Oxygen radicals) into the chamber. These techniques utilize plasma generating systems producing appropriate free radicals which can operate at pressures of 2-10−4 Torr and generate radical, e.g. atomic Oxygen (O0) particles, which react with contaminates in the vacuum chamber and enable evacuation thereof.